The purpose of this controlled, randomized clinical trial (RCT) is to compare the differential efficacy of an acute phase of cognitive therapy (CT) followed by an 8-month continuation phase to an acute phase of CT without a continuation phase in reducing the probability of relapse/recurrence during the first 8 months following acute treatment in outpatients with recurrent major depressive disorder (MDD). This study is important because MDD is prevalent, has high economic and human costs, and recurs in approximately 50-85% of cases. Our pilot data suggest that with continuation CT, the probability of relapse/recurrence can be decreased to 19% during the 8 months immediately following an acute phase of CT. Without a continuation phase, the relapse/recurrence rate was 48% within 8 months post-acute CT. Life table methods show a trend for the cumulative survival times to differ over 8 and 24 months (p = .10; n = 47). If within the first 8 months following the acute CT phase the relapse/recurrence rate is 30% or less, we will judge such prophylaxis to be clinically significant and conclude that CT for recurrent depression may offer an alternative to continuation by pharmacotherapy. This study is the first controlled, randomized evaluation of the probability of relapse/recurrence following an acute phase of CT. It is also the first CT study aimed specifically at outpatients suffering from recurrent major depression. In contrast to the available studies, relapse/recurrence is defined as meeting RDC for major depression and having a HRS-D score > 16. Follow-up is controlled rather than naturalistic. Secondary aims of this study include (a) collecting preliminary data on the efficacy of CT with and without a continuation phase in reducing relapse/recurrence during 24 months of acute treatment in patients who survive the 8 month RCT, and (b) identifying the extent to which demographics, pre- and posttreatment clinical, cognitive, interpersonal, and personality functioning predict response, relapse, recurrence, remission or recovery. Approximately 144 male and female outpatients, aged 20-65, with unipolar, nonpsychotic, recurrent major depressive disorder will enter 20 sessions of acute phase CT. Approximately 72 remitters will be randomized to either the 8 months of: (a) 10 continuation CT sessions, or (b) 10 CT- free evaluation sessions only. The competency of cognitive therapists will be monitored longitudinally. Dependent variables will measure response, relapse, recurrence, remission and recovery. Blind evaluations occur at the end of the acute phase, at 4, 8, 12 and 24 months post-acute CT, and at suspected relapse/recurrence, or exit. Diagnostic evaluations occur for the first 12 months post-acute CT and bimonthly for the second 12 months post-acute CT. Survival analyses are planned.